Telephone protector modules have reached a state of very high development in the prior art. They serve the purpose of providing for the grounding of surges of excess voltage and current occurring in an individual telephone circuit, which current surges may be of either a momentary type, as occurring during a stroke of lightning which strikes the circuit, or of a substantially continuous type, as might be caused by a falling power line contacting the circuit. Most such devices include a heat sensitive means actuated by the presence of the latter type of surge, wherein one or both lines are placed in electrical communication with a grounding prong, in turn communicating with a source of ground potential. This actuation preferably bypasses the flow of excess current through an arcing device provided for grounding momentary surges of excess current, so as to avoid damage to the arcing device.
The protector devices are normally mounted upon a connector block mounting hundreds of such modules in juxtaposed relative locations. Upon the actuation of a heat sensitive device, to ground an excessive current, the circuit remains grounded (and the related subscribers remains without service) until the source of trouble is corrected, and the protector module is replaced.
In the past, the locating of a "blown" module included stroking contacts of many individual telephone lines on a telephone connector block using a probe connected to a volt meter, a laborious process, complicated by the fact that there are normally a large number of such contacts positioned as closely adjacent each other as possible. As it is usually impossible to label grounded circuits, the modules have to be replaced individually as they are identified.